My guess is that you're running a non-privileged container. systemd requires CAP_SYS_ADMIN capability but Docker drops that capability in the non privileged containers, in order to add more security.
systemd also requires RO access to the cgroup file system within a container. You can add it with –v /sys/fs/cgroup:/sys/fs/cgroup:ro
So, here a few steps on how to run CentOS with systemd inside a Docker container:
Pull centos image
Set up a docker file like the one below:
FROM centos
MAINTAINER “Yourname" youremail@address.com
ENV container docker
RUN yum -y update; yum clean all
RUN yum -y install systemd; yum clean all; \
(cd /lib/systemd/system/sysinit.target.wants/; for i in ; do [ $i == systemd-tmpfiles-setup.service ] || rm -f $i; done); \
rm -f /lib/systemd/system/multi-user.target.wants/;\
rm -f /etc/systemd/system/.wants/;\
rm -f /lib/systemd/system/local-fs.target.wants/; \
rm -f /lib/systemd/system/sockets.target.wants/udev; \
rm -f /lib/systemd/system/sockets.target.wants/initctl; \
rm -f /lib/systemd/system/basic.target.wants/;\
rm -f /lib/systemd/system/anaconda.target.wants/*;
VOLUME [ “/sys/fs/cgroup” ]
CMD [“/usr/sbin/init”]
Build it - docker build --rm -t centos7-systemd - < mydockerfile
Run a container with docker run --privileged -ti -e container=docker -v /sys/fs/cgroup:/sys/fs/cgroup centos7-systemd /usr/sbin/init
My guess is that you're running a non-privileged container. systemd requires CAP_SYS_ADMIN capability but Docker drops that capability in the non privileged containers, in order to add more security.
systemd also requires RO access to the cgroup file system within a container. You can add it with –v /sys/fs/cgroup:/sys/fs/cgroup:ro
So, here a few steps on how to run CentOS with systemd inside a Docker container:
Pull centos image Set up a docker file like the one below:
FROM centos MAINTAINER “Yourname" youremail@address.com ENV container docker RUN yum -y update; yum clean all RUN yum -y install systemd; yum clean all; \ (cd /lib/systemd/system/sysinit.target.wants/; for i in ; do [ $i == systemd-tmpfiles-setup.service ] || rm -f $i; done); \ rm -f /lib/systemd/system/multi-user.target.wants/;\ rm -f /etc/systemd/system/.wants/;\ rm -f /lib/systemd/system/local-fs.target.wants/; \ rm -f /lib/systemd/system/sockets.target.wants/udev; \ rm -f /lib/systemd/system/sockets.target.wants/initctl; \ rm -f /lib/systemd/system/basic.target.wants/;\ rm -f /lib/systemd/system/anaconda.target.wants/*; VOLUME [ “/sys/fs/cgroup” ] CMD [“/usr/sbin/init”]
Build it - docker build --rm -t centos7-systemd - < mydockerfile Run a container with docker run --privileged -ti -e container=docker -v /sys/fs/cgroup:/sys/fs/cgroup centos7-systemd /usr/sbin/init
You should have systemd in your container